Isolation, characterization, and bioactivity of stilbenoids from Cyperus conglomeratus with in vitro and in silico antidiabetic evaluation

An investigation into the chemical constituents of the ethyl acetate extract of Cyperus conglomeratus resulted in the isolation of one stilbene dimer and a stilbene trimer from this species for the first time. Their structures were identified as (E)-scripusin B (1), (E)-cyperusphenol A (2) based on 1D and 2D NMR techniques, along with HR-ESI-MS. Compounds 1 and 2 were assessed for their antioxidant, antidiabetic, and prebiotic activities. The antidiabetic activity was achieved through the inhibition of enzymes such as α-glucosidase, α-amylase, and glycogen phosphorylase, while the prebiotic activity was evaluated across various Lacticaseibacillus species, measuring the impact on probiotic growth rate, Pscore, and enzyme profile. Compound 1 exhibited a higher α-glucosidase inhibition (IC₅₀ = 1331 ± 6.22 µg/mL), whereas compound 2 demonstrated greater inhibitory activity against α-amylase (IC₅₀ = 1097 ± 5.34 µg/mL) and glycogen phosphorylase (IC₅₀ = 1670 ± 5.28 µg/mL). The observed inhibitory activities of both compounds against the enzymes were supported by molecular docking studies, providing a rational explanation for the results. Additionally, the compounds displayed a concentration-dependent increase in antioxidant activity. The prebiotic activity results revealed the positive values of Pscore, indicating that the growth rate of the prebiotics was enhanced in the presence of isolated compounds. The findings suggest that C. conglomeratus represents a promising source of natural antidiabetic, antioxidant, and prebiotic agents, due to its rich stilbenes content. Notably, the prebiotic potential of stilbenes from C. conglomeratus was investigated for the first time. These findings underscore the necessity of further exploration for the potential formulation of functional foods or nutraceuticals based on this species.